|Year : 2016 | Volume
| Issue : 4 | Page : 232-234
Renal cell carcinoma in a horseshoe kidney: Report of a rare disease
Kehinde Habeeb Tijani, Rufus Wale Ojewola, Dubem E Orakwe, Abisola E Oliyide
Department of Surgery, Urology Unit, College of Medicine, University of Lagos/Lagos University Teaching Hospital, Lagos, Nigeria
|Date of Web Publication||20-Dec-2016|
Kehinde Habeeb Tijani
Department of Surgery, Urology Unit, College of Medicine, University of Lagos/Lagos University Teaching Hospital, Lagos
Source of Support: None, Conflict of Interest: None
A horseshoe kidney (HSK) is the most common congenital renal fusion anomaly. HSKs are more likely than normal kidneys to have associated problems of stones, ureteropelvic junction obstruction, stasis and infection. However, they do not have an increased incidence of renal cell carcinoma when compared to normal kidneys. Due to its rarity, accurate diagnosis may be difficult. Of similar significance is the fact that problems may arise during surgery on these kidneys due to altered anatomy and aberrant blood supply. We report a case of HSK with a renal tumour in a 69-year-old woman and highlight our challenges in the management of the case. To the best of our knowledge, this is the first reported case of a tumour in an HSK in West Africa
Keywords: Horseshoe kidney, isthmus, renal cell carcinoma, West Africa
|How to cite this article:|
Tijani KH, Ojewola RW, Orakwe DE, Oliyide AE. Renal cell carcinoma in a horseshoe kidney: Report of a rare disease. Niger Postgrad Med J 2016;23:232-4
|How to cite this URL:|
Tijani KH, Ojewola RW, Orakwe DE, Oliyide AE. Renal cell carcinoma in a horseshoe kidney: Report of a rare disease. Niger Postgrad Med J [serial online] 2016 [cited 2019 Aug 22];23:232-4. Available from: http://www.npmj.org/text.asp?2016/23/4/232/196268
| Introduction|| |
A horseshoe kidney (HSK) is the most common congenital renal fusion anomaly affecting approximately 1 in 400 live births.  HSKs are more likely than normal kidneys to have associated problems of stones, ureteropelvic junction obstruction, stasis and infection.  However, they do not have an increased incidence of renal cell carcinoma (RCC) when compared to normal kidneys.  Of great significance is the fact that problems may arise during surgery on these kidneys due to altered anatomy and aberrant blood supply. We report a case of HSK with renal tumour in a 69-year-old woman and highlight our challenges in the management of the case. To the best of our knowledge, this is the first reported case of a tumour in an HSK in West Africa.
| Case Report|| |
A 69-year-old retired teacher was referred to us on account of recurrent dull colicky non-radiating left loin pain spanning 2 years before presentation with no aggravating or relieving factors. She denied a history of haematuria. Apart from the chronic use of tobacco (snuff) and lisinopril for systemic hypertension for 8 years, review of all systems was essentially normal.
She was initially referred from a private hospital to the nephrology clinic of our centre where she presented two conflicting ultrasound scan (USS) reports. The first reported a tumour in the lower pole of the left kidney while the second scan reported no tumour. However, both scans reported a small/shrunken right kidney. A repeat USS at our centre reported a tumour in the upper pole of the left kidney. She was finally referred to the urology clinic 5 months after presenting to the nephrologist. The essential findings on examination were the presence of mild pallor and the presence of a firm, non-tender, 8 by 8 cm mass in the left lumbar region. An initial diagnosis of a left renal tumour to rule out hydronephrosis was made. Laboratory investigations were normal apart from haemoglobin of 9 g/dl.
The preliminary report by the radiologist of an abdomen-pelvic computed tomography (CT) scan also suggested a localised tumour involving the left hemi-kidney (LHK) in HSK [Figure 1]. She was subsequently prepared for surgical exploration. The essential intraoperative findings included a 13.5 cm diameter tumour confined to the isthmus and inferior two-third of the shrunken right hemi-kidney (RHK). The tumour was most bulky on the left side of the isthmus [Figure 2]. A partial duplex collecting system was draining the RHK and right side of the isthmus while a single pelvis appeared to drain the LHK and left side of isthmus. The isthmus (tumour) was supplied by an anterior branch of the aorta that originated at the level of the aortic bifurcation, while the LHK appeared completely spared from the tumour with a clear margin of normal tissue separating them. After ligating the right renal vessels and the aberrant artery, the RHK and isthmus were resected en bloc and sent for histology. The raw lower pole of the left kidney was repaired with a retroperitoneal drain left in situ. The post-operative period was uneventful except for prolonged drainage of urine through the drain. She was finally discharged 2 weeks after surgery.
|Figure 2: The left side of the tumour (green arrow), lower pole of the left kidney (orange arrow), line of demarcation between left kidney and isthmus (blue arrow), and bulldog clamp applied to the aberrant artery (purple arrow). Note the gradual discoloration of the tumour|
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On pathological examination, the 300 g specimen measuring 13.5 cm × 9 cm × 4.5 cm was irregularly shaped and multilobulated. Tumour mass within the specimen was located in the isthmus and the inferior pole of RHK, well circumscribed and demarcated with pelvicalyceal distortion. It measured 7.5 cm × 6 cm × 4.5 cm extending anteroposteriorly and at a distance of 7 cm from the superior pole and 3 cm from the horseshoe segment. Histology confirmed a diagnosis of clear cell RCC with tumour-free surgical margins. At 2 years follow-up, she was alive and well.
| Discussion|| |
Renal tumours in HSK are uncommon with <200 cases reported in the literature. ,,, Indeed, RCC involving the isthmus is exceedingly rare  and to the best of our knowledge, this will be the first case reported in Sub-Saharan Africa. Various histological types of renal malignancy in HSK have been described with RCC comprising about 50% of tumours followed by transitional cell carcinoma and Wilms' tumour.  RCC is, however, not more common in HSK than in the normal population.  Transitional cell carcinomas, on the other hand, are said to be more common in HSK probably due to chronic urinary tract infections.  The highest incidence of RCC is in the seventh and eight decades of life and the generally accepted risk factors for RCC include tobacco exposure, obesity and hypertension.  Our patient was 69-year-old, had a history of prolonged tobacco exposure and was hypertensive, which further suggests that patients with HSK s are at same risk of developing RCC as the normal population of the same age exposed to such risk factors.
The highly variable blood supply of an HSK constitutes a serious concern during surgery. , In our patient, a ventral branch of the aorta supplied the isthmus. Even though pre-operative renal angiography was not done for this patient due to financial constraints, it is currently recommended to accurately delineate the vascular supply for effective planning and the prevention of serious intraoperative morbidity. , Despite this limitation, the resection of the tumour for this patient was technically straightforward because the vessels were easily identified during the early phase of the surgery.
Due to its rarity, the diagnosis of tumour in an HSK can be confusing as was highlighted in this case where three different USS reported different diagnoses while the preliminary report of the pre-operative CT scan also suggested a tumour in the LHK. However, the intraoperative, histological and post-operative CT findings [Figure 3] confirmed tumour involvement of only the isthmus and the RHK with a normal LHK. The fact that the most bulky part of the tumour was at left part of the isthmus probably contributed to the challenges faced in the pre-operative side localisation of the tumour. Prognosis is unaffected by the anomaly and is dependent on tumour pathology and stage at diagnosis just as in normal kidneys. A high index of suspicion is however required to make an early diagnosis of a tumour in an HSK.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]